Immersion pulmonary edema is sudden-onset pulmonary edema that typically occurs early during a dive while at depth.

Immersion pulmonary edema has become more common over the past 2 decades. This disorder is similar to negative pressure pulmonary edema encountered during induction of anesthesia or after extubation, when a patient with laryngospasm attempts to take deep breaths against a closed larynx, thereby causing negative intra-alveolar pressure. Abnormal left ventricular systolic or diastolic function may contribute. Immersion pulmonary edema is not related to pulmonary barotrauma or decompression sickness. Cold water and a history of hypertension are risk factors. This syndrome occurs in competitive open water swimmers.

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